Paraffin alkylation



a Kl l 6., R Y F 6 A,3 E H ,s RK 2 om .m TR NE O ED \T.. ma w A .I .r

.Wx Y B N T 9 H S H H vx A l V 3 V V G u E L 3 V d 9 D 3 R m 2 u m V V |ll* L H A D N .I l un N 3 N ua E N e V .I I IA V Vv Vv O I F H. i W. 1 M D M 9 F W.. d N W. N N 3 mm .l W V d M P F 3 M.. V W W O 3 3 W H. mw V V 8 N N s S S mr mZ-Mhm/ Jan. 9, 1945o Patented Jan. 9, 1945 l PARAF'FIN ALKYLATION- Frederick Frey, Bartlesville, Okla., asslgnor 4to Phillips Petroleum Company, a corporation of Delaware n l Application February 2, 1940, Serial No. 317,017

A 7 claims. (o1. 26o-683.4) This invention relates to 8,' process of manudrawing, which shows a flow-diagram for a pre- "facturing .fhydrocarbons o f relatively high ferred mode of operation, adapted to produce molecular Weight fromhydrocarbons .of lower hydrocarbons boiling in the motor-fuel range.

molecular weight, and more particularly to the A feed stock comprising atleast one paran manufacture of motor.-fue 1 hydrocarbons from 5- hydrocarbon having from two to six carbon "lower-boiling hydrocarbdr-1s..{It:is4 a continuatoms permolecule enters the system through "ation-'in-partzotlzny c'opendingfapplication Seinlet v`I having control-valve 2. It passes into ria1'No.'312,964, iiled January 8,1940.l Y dehydrogenator 3, in which part of the feed I have found thatmelatively high-boiling hystockris lconverted into at least one unsaturated drocaifbonsflnayfhe. manufacturedirom..lower-T10 hydrocarbon. For example, dehydrogenator 3 i1ing hydrocarbons,'such as' parainsjand/orf may' lbe a cracking coil in which the paraiiin j'- oleiins, by converting the lower-boiling hydrohydrocarbon is cracked into unsaturated hydrocarbons'finto alkylhalides, such as chlorides or carb'ons; more advantageously, itmay be a cataluorides,"and"subsequently alkylating p araiiins;` "lytic dehydrogenator ih which one or more of especially isoparains, vwith the ralkyl `halidesf15 the known catalysts for cracking and/or dehy- @under suitablel alkylation conditions. I have drogenating hydrocarbons into unsaturated hyvfurtherffound that the alkylation reaction is drocarbons are used; Particularlyefcient cata-V l favored by the paraiiin having a branched struclysts `forthis purpose comprise` black unglowed V"turegwith a tertiary hydrogen atom and bythe chromium oxide; butmany other catalysts, such alkyl group of the alkyl halide being ,non-pri-` 20 as bauxite and alumina, withor Without'promoiria-ry, A that is, secondary or tertiary. Furtherters such as compounds of "chromium, zirconium,

more, I have found that alkyl chlorides are more molybdenum, etc.. maybe used withgood results. *advantageous than other halides forthea1ky1- As parafns havinggmore than four carbon ation orparaiilns. I `atoms per molecule may be readily .incorporated An' Object of this invention is to c iect the v25 as such in motorffuel, the feed stock to be dehymanufacture of relatively higher-boiling hydro- 'drogenated may comprise advantageously chiefcarbons from lower-'boiling hydrocarbons... "ly at least one'paraiiin having two to four car- Another object is to convert lower-boiling hybon atoms per molecule; furthermorg as isobudrocarbonsl'into motor fuel by alkylation of partane may be utilized efiiciently in a subsequent Vafiins with alkyl'halides formed from .low-bolla 30 step, the feed stock advantageously may comh1'3j-ing hydrocarbons; f .prisechieily at least, one of the normally gase- Another object is to convert hydrocarbons' havlcus unbranehedparaiiins, ethane, propane, and

` ing two to six carbon atoms per molecule -into normal butane. alkyl chlorides Suitable fOr the alkylation -of VFrom dehydrogenator 3, the products and un- .isoparailns `35 reacted hydrocarbons may be passed through Another objectis to decrease` the volatility of` valve 4 and conduit' into fractionating means Daralins, especially isoparafns. Y Iii which serves chiefly to remove light gases such Another *object is to utilize 4hydrogen chloride ashydrogen and methane; these are withdrawn in a' processor manufacturing-motorio@ hydroas a light-gas :fraction through valve 1 and `carbons from` lower-boiling hydrocarbons hav- 40 `outlet'. If desired under someconditions of ing two to eightcarbonv atoms per molecule. operation, ethane and ethylene may be removed A furthery objectgis to produce', entirely from, with hydrogen and methane. The residual hylower-boiling paralinahigher-boiling paraflins droc'a'rbons are passed through valve 9 and con- A further/ object isto producefpreselectedparduit I to reactor II. 'aflin l'iydrdcarbo'nsfrom lower-boiling vparaffin 45 I f desired,"under some conditions of operation,

hydrocarbons. at least part of the eiliuent from dehydrogenator Another-'object is torecover and toutilize ole- 3 may ne passed through valve l2 and by-pass fnS from gaseous mixturesby'convertingthem conduit IBdirectly to conduit I0 and thence to into halicles,4 which are kreadily condensa-lola or reactor' Il without undergoing fractionation in extratablefand then reactingv them with per- 5o fracucnating means 5. Also, if desired, a -feed aflns yt0 l y'i'elCl higher-boiling Vllfflllfls. stock comprising atleast one olefin having two to Other objects and advantages of the invention six carbon atoms per molecule may enter the sys- 'will be obvious to those skilled in the art. tem, as through inlet I4 having control-valve I5,

The invention will be readily understood from and be-passed to reactor II, as by conduits I3 the following description and the accompanying 55 and Il).`

. advantageous for the ride.

Simultaneously with the passage of oleflnic l' hydrocarbon material into reactor I I, a hydrogen halide, preferably hydrogen chloride, enters the l system at inlet I6 having control-Valve I1 and passes through conduit IB, together with recycled hydrogen halide from. conduit I9, to reactor II. Although hydrogen chloride is preferred, other halides, especially hydrogen fluoride, 'may be hydrogen iodide are undesirable under-'some conditions of operation because the alkyl bromides and iodides they form are subject to loss by oxidation that aredifiicult to reclaim.

into by-products In reactor I I, the mixture comprising olenic hydrocarbon material and hydrogen halide is subjected to conditions favoring union of the olens with the hydrogen The conditions depend somewhat upon the particular reactants, but a suitable temperature and a suitable pressure may be readily found between and 400 F. and between 1 and l0 atmospheres, respectively; however, temperatures and pressures outside these ranges at times may be useful. In

halide to form alkyl halides.

general, a temperature below about 150 F. is

productionof tertiary alkyl halides, and' one above this temperature for'the production of secondary and primary alkyl halides. Although the reaction is capable of occurring in the absence .of a catalyst, the rate of reaction under most conditions is advantageously increased by a catalyst comprising at least one corresponding halide of a polyvalent metal.

Among suitable catalysts are the halides of tin,

zinc, antimony, aluminum, bismuth, vanadium, manganese, barium, calcium, cadmium, copper, chromium, iron, mercury, nickel, and similar polyvalent metals. Of these catalysts, the chlorides of barium, tin, zinc, and antimony are preferred for the reaction involving hydrogen chlo- Other catalysts, including metallic oxides and .mineral acids and acid salts and even Water catalyze the reaction, and suitable catalysts and conditions are readily determined by trial.

l The catalyst may be supported on a porous ma-l terial such as charcoal, Vsilica gel, alumina gel, fire brick, and similar well-known supports, or it may conduit an intermediate fraction through valve 29 and charged from the system, entirely .or in part, through conduit ,68 and valve 61, or may be returned to reactor I I, entirely or in part, from conduits 30 and B8 through conduit 1n and valve 1I to conduits I9 and I8. Also, if desired, at least part of the eiiiuent from reactorv I I may be passed through valve 3I and conduits 32 and 21- directly to alkylator 2B Without undergoing fractionation in fractionating means paraffin having four to eight carbon atoms, such as natural-gasgasoline, Wild extracted hydrocarbons'from natural gas, light petroleum distillates, and rthe like, may enter the system through inlet 33 having control-valve 34'and pass through conduits 32 and 21 into-alkylator 28; such isoparamn advantageously may be isobutane, as heavier paraflins may be incorporated as such in motor fuel more readily than isobutane.

In place of going through the steps of dehydro-v genating the paraiflns charged to the process through conduit I, and reacting the oleiins witha hydrogen halide, or in case an olefin-containing stream is not available to be charged through conduit I4, parafiins may be reacted directly with free halogen to produce alkyl halides and the corresponding hydrogen halide". In such a. m'odication, the use of chlorine is to b preferred, not only because alkyl chlorides are preferred for subsequentuse, but because chlorine is cheap andl the chlorides are readily handled. Inl this modification, the parafiin hydrocarbon material from which alkyl halides are to be `mad`e 'is ycharged through conduit I4 and valve I5, and a freehalogen is charged through conduit I6 and valve I1.

' reactions. In such acase, ofcourse, dehydrobe dispersed in aliquid medium such as chlorli nated hydrocarbon, which preferably has a boiling point Ihigher than that of the alkyl chloride to be formed and into which the reactants are injected.

After 'the reaction between olef'lns and the hydrogen halide is resultant mixture is passed from reactor II through valve 20 and conduit 2| into fractionating means 22, wherein it is fractionally distilled and separated or wherein thevalkyl halide insome instances is separated from the mixture by condensation or simple absorption in a low-boiling hydrocarbon liquid, suchl as natural gasoline, introduced through conduit 1.5. `Any undesired light gases, such as hydrogen and hydrocarbons having less than two 'carbon atomsper molecule may be removed as a light-gas fraction through valve 23 and outlet 24. Unreacted hydrogen halide may be recycled to reactor II through valve 25 and conduits I9 and I8, or may be discharged from the system, entirely or in part, throughconduit 65 and valve 66. The alkyl halide, together with, if desired, at least a part of the unreacted hydrocarbons, is passed as a heavy fraction through valve 2i;l and conduit 21 into alkylator 28,

If desired, unreacted hydrocarbons having two carbonatoms per molecule and a part or'all of the other unreacted hydrocarbons may be recycled as substantially completed, the l genator 3 and fractionating means 6 n'eed not, be included, and subsequent parts, and operation, of the process will be substantially the same. This modification results in the production of sub'- stantial amounts of a hydrogen halide which may be removed from the process or which may be used for producing additional alkyl halides from olens in another reactor in the manner already described. If the hydrogen halideis not used to react With olens, free halogen can be regenerated from it, if desirable, by chemical oxidation, electrolysis, or the like, and re-used in the halogenation step. The halogenation does not require drastic reaction conditions, and the conditions are readily controlled, when paraflins of more than two carbon atoms per molecule are used, so

as to produce high yields of non-primary alkyl halides, which form the most desirable charge to the subsequent alkylation step.

If a hydrocarbon stream containing botholens and paraflins is charged tothe process, the olens may be reacted in reactor IIl with a hydrogen halide. and unreacted parafflns, separated from the eiliuent, either may be dehydrogenated, as previously discussed, or may be reacted with free halogen to form alkyl halides in supplemental apparatus similar to that shown and discussed; the effluent from such a halogenation step may be added to the material flowing through conduit 2 I, as will be readily appreciated.

In alkylator 28 the mixture entering it through conduit 21 and comprising an'alkyl halide and a paraffin having four to'eight carbon' atoms per 30 to dehydrogenator 3, or may be dis-` 22. Furthermore, if devsired, a feed stock comprising at l'east one isomolecule is subjected to suitable alkylation than sulfuric acid tiary react some the alkylation reactants.

conditions. These conditions comprise the presence of an alkylation catalyst such as aluminum halides, double'salts of aluminum halides, such as so- ,dium chloride-aluminum chloride, and other catalysts adapted to effect alkylation of paraiilns with alkyl halides, such as concentrated sulfuric acid. 4If a mobile catalyst, `such as sulfuric acid,

A is used, it enters the alkylator through inlet 35 having control valve 36.

The choice of a suitable catalyst depends somewhat upon the alkylation reactants. For example, primary halides, especially ethyl halides, react relatively diflicultly andrequire a catalyst more powerful than that which is adequate for non-primary alkyl halides. Thus, when a primary alkyl halide, such as ethyl chloride, is used, catalysts of the aluminum chloride type are more advantageous than catalysts of the sulfuric acid type.

Various reactions occur in alkylator 28, but the 'I ress of the reaction may primary reaction is believed to be alkylation of paratllns, especially isoparaiflns, which are alkylated more easily than normal paraiiins, with an elision of a hydrogen halide:

dergo secondary reactions that form lower-boiling and higher-boiling products; it doubtless also undergoes isomerizatin `As alkylation in is well-known to the art, additional description 'of the alkylation step will be limited, primarly for the sakeof brevity, to sulfuric acid alkylation. When sulfuric acid is used as the catalyst, the alkylation reaction appears to proceed mostv el'iciently` for isoparaflins having four to eight carbon atoms per molecule and for 'non-primary alkyl halides in which the alkyl group has three to six carbonlatoms per molecule. Of non-primary alkyl halides, the terwha't more rapidly than do the corresponding secondaryalkyl halides; hence; as

tertiary. alkyl halides are produced from the reaction of hydrogen halide with only isool'ens, it is advantageous for the feed stock to the dehydrogenation step to comprise chiefly an isoparafiin, especially isobutane, if an adequate supply of such isoparaifln is available. Conversely, if a secondary alkyl halide is used in the alkylation step,

- it is advantageous to use a relatively high strength of acid, such as 100 to 105 especially if the halide is tion is favored by a relatively high ratio of sulfuric acid to hydrocarbons; the acid should have a volume within the range of 0.1 to2 times the volume of hydrocarbons, advantageously within the range of 0.5 to-l. The sulfuric acid shouldhave a composition equivalent to Aa strength within the range of 90 to 105 per cent `by weight, preferably between 95 and 102 per cent; the reaction temperature may be in the range of 0 to 125 F., preferably between 50 and 100 F. side, the acid may `contain emulsiiiers, such as for example akyl sulfates. As alkyl sulfates or equivalent compounds are formed to some extent during the reaction, a small portion of spent acid advantageously may be added to fresh acid to increase its ability to form good emulsions with per centsulfuri acid, a chloride. The reac- The Ireaction requires sometime to approach completeness, but a period of -from 5 minutes to 3 hoursis usually suilicient. Much longer perlods preferably should be avoided, as they favor thepresence of catalysts other cycled to dehydrogenator3 and/or alkylator If dethrough valve 44 and. conduits hydrocarbon products boil chiefly in the motor-Y into a motor-fuel ,through valve 56 and outlet 51;

secondary reactions that convert the primary alkylation product into lower-boiling and higherboiling products. Some indicationy of the progbe obtained from the rate of evolution of hydrogen halide, which is a product of the primary alkylation reaction. The

fuel range, are substantially completely saturated, and have excellent anti-knock ratings..

After substantially all of the alkyl halide has reacted, the resultant mixture is passed through valve 31 and conduit 38 into separating means 39, in which the sulfuric acid is separated from the mixture as a heavylayer by gravity or, if desired, by centrifuging. The sulfuric acid may be withdrawn through valve 40 and outlet 4i,

and thencet may be subjected to a process of reclamation, if desired; or, alternatively, it may be returned, partly or entirely as trial indicates is desirable, to alkylator 28 through valve 42 and conduit 43. The hydrogen halide is passed 45, I9, and I8 to ain to form alkyl ed,v entirely-or in alve 12. The hyreactor Il, in which it is used ag halides, or it may be discharg part, through conduit 13 -and v l drocarbo'n material is` passed through va1ve-46 and conduit 41 to alkali treater 48, in which it is freed lfrom acidic material by a Washing. treatment with an alkali.

From alkali treater 48, th is passed through valve fractionating means 5 l Under some conditions of operation, a small amount of acidic material in the hydrocarbon material passed to fractionating means 5| may be tolerated; under such conditions, if desired, at least part of the hydrocarbons from separator 39 may be passed through valve 52 and conduits 53 and 50 directly to fractionating means 5I Withe hydrocarbon stream 49 and conduit 50 to out being subjected to an alkali treatment in alkali treater 48.

l In fractionating means are fractionated .into a heavy-oil fraction, which is withdrawn through valve 54 and outlet 55; fraction, which is withdrawn and into one, or two,- low-boiling fractions, which may be rethrough conduits 58 and/or 59 in proportions controlled byvalves 60 and 6|. If desired, either or both of these fractions may include at least volatility by4 being reprocessed; fraction recycled to alkylator 28 59 may include any alkyl halide furthermore,` the through conduit through the valved conduits sho It will be understood that a not sh sirable or necessary.

The term isoparafiin, as use to paraiin hydrocarbons such as isobutane (2- 5l, the hydrocarbons d in this specication in connection with the charge stock, refers some part dltmetl'iylpentane ands 3fethylpentane, and the When it is desired'to. produce a; gasoline hay ing particularly desirable characteristicasueh as.

an aviation gasoline, or' some cert-.aim valuableshydrocarbon or hydrocarbonsboilingin the mir-` tor-fuel range, it will generallynot be. desirable;

per. cent is mentioned,` reference is;` made; to' "fuiming sulfuric acid which-.when'titrated with an alkali, reacts with suicient alkali to. be equivto use an isoparalilnhavingaI molecular weights l higher than that oi isobutane--on of -isopentanaor possibly of isohexane. lWhenlit-isdeslred to produce paraiiins boilingv abovef the, motorduel: rango, correspondingly heavier,llaralfmsl shouldv he charged. It has been; found, that highly hrahchedy isoparaiiins oi relatively high molecul lar weight are somewhat readilydeoomposed by prolonged Contact with sulfuriczacid: whenthese are used the reaction conditions'. shouldl beso modified, as indicated by trial; that extensive deleterious decomposition does not take place,

or at times it lmay be more desirable,` toicha-rge. a`

simple isoparafn such as2me`thylheptane or2; 4-dimethylhexane than to icharge-a'complex isnparan such as 2, 2, 4-trmethylpentane.

It vvll. of course, generally be mpracticalto charge any parti-cular hydrocarbon in an ab sel-.ltely pure state. especially when relatively nien-boiling hydrocarbons. used. en mar individual pzuxafn is desired to bg Obtane ln a. relatively p re State., as by flactlonal distillation of the renc ion mixture dr carbon ix 1re charged. shauldmb I ispaxamns are re Y arnountsk of normal pairan's Vis generally nob- 4;

deleterious, and may at timesbe advantageous in controlling the reaction; atother'times, less pure vhydrocarbon yfractions may be used. As previously mentioned, it is preferable to use either secondary or tertiary alkyl lialides-,and it is also preferable that the hali'des be chloridesv It is one of the features of my invention that the alkyl halides produced in the rst part of my process are' readily separated from the other constituents of the reaction mixture and are also of the most desired type for the vsi'ibsequental-H kylation step. Hydrocarbons. of relatively lowmolecular weight are readily reactedin this first part of the process, with the minimum of side reactions.v and the resultant alkyl halides are readily obtained in a pure state when desirable, such as when it is desired toproduce a gasoline, or some certain valuablef'hydrocarbon or 'hydrocarf bons boiling in the motor-fuel range. In any y case where such a particular hydrocarbonv product'isdesired, the individual hydrocarbons suitable rfor the charge stock.may be readily selected by trial, in 'thelight of .thepresent disclosureL For t'ie,acidfalkylationstep, the temperature, the' reaction time', andthe. relative amount of sulfuric acid are interrelated. With relatively high temperatures and/orlarge amounts of acid, relatively' short reaction times may be used.

When itis desired to' producea relatively pure product, short reaction times, and low yields per'pass should characterize all vthe steps of the process, and. when ascertain appreciable amount of. side reactionsousecondary` reactions may 'be tolerated, vall the stepsrof the process may be operated ,so as to haverlonger reaction times and higher yields per pass. The-most desirable conditions in any particular instance fcan be readily determined by trial. v y

When sulfuric acidstrength infexcess of 100 alent to the amountofacidindicated The following: examples `are given purely for. the purpose of illustrating a few-of thev manyV possible modesA off operation of the processrthey: aregnct necessarily to be takenaas. establishing,

limitations. ofl` the invention.E Exdmplel.

A-ieed stockA comprising chiefly isobuiane is de hydrogenahd with a catalyst comprisingy hlach `orador/eri chromiumk oxide ata pressui'einthe room -unoondensed light hydrocarbons areremoved;

The residual material is n'xeclfwithV anhydrous hydrogen chloride approximately equivalent :in amount, to the sobqtylene. whereupon tertiary butyl chloride is formed: ,the reaction occurs rep-dry er. prdinery temperatures and pressures. The resultant. Vmixture of-isobutene s nd tertiary butyl chloride is intimately mixed as 2. liquid at emperature' with ab t three-3215215 of its concentrate sul: rie eeid he. ine:

about per een se me er and the mlxeure is snowed te react for about four hours. n) hydrogen chloown volume of s.. strengere of iven sei xxxx r.

vride regenerated by the reactionds recycled to The sulfuric acid is removed by settling, and the hydrocarbon matehaving rial is freed lfrom residual acidic materlal'by washing with dilute alkali. This hydrocarbon material is substantially completely paraflnicA and has a substantial content of hydrocarbons `molecule; it is fractionated. into aniisobutane fraction, which is recycled to the dehydrogenation step,` and into a motor-fuel fraction, which is withdrawn from the system and has a high'.

antiknock rating.`

Example II Tertiary butyl chloride isprepared from isobu.

tane. and hydrogen chloride vas. in Example 1'.

' Itis freed from` isobutane by fractional distillation, the isobutane being recycled to the dehy- Itvisthen mixed with about:

drogenation step. 1.5 times its own weight of. a feed stock comprising chiey isopentane, and the resultant mixture is lemulsied by mechanical stirring, with about4 three-fourths of its own volume of yconcentrated sulfuric acid having a strength of 96.per cent by weight. After about. four hours at a temperature of about 70? E, during-Which theregenep ated hydrogen chloride is recycled to` the step4 for forming butyl chloride, the emulsion is allowed to settle into. two layers. The Alower or acid .layer is;removed, and the upper or hydrocarbon layer is lWashed with-dilute-,alkali and then fractionally distilled. O'f the hydrocarbons otherV than lisopentane, about 96 per cent by weight boil between 85 and410?V F.; this fraction amounts to about 83 per cent` by-Weight of the theoretical yield based on. theformation of nonane. The motor-fuel fraction oftheproduct su formed has a good antiknoc-k rating .and aBei'd' vapor pressure of less than 4 poundsl more than four carbon atoms perV Example III A feed stock comprising chiefiy normal butane is dehydrogenated, in the presence of dehydrated bauxite, at a pressure of about 1 atmosphere,-at a temperature of about 1000 Vto l200 F., and at a space velocity of about 1000 volumes of butane, calculated to 32 F. and 1 atmosphere, per volume of catalyst per hour. The eiuent is cooled and compressed until the four-carbon hydrocarbons and most of the threecarbon hydrocarbons are liqueed; hydrogen and uncondensed light hydrocarbons are removed.` The residuali material is mixed with anhydrous hydrogen chloride slightly in excess of the amount chemically equivalent to the olens present, and is subjected to the actionof a catalyst comprisingzinc chloride supported on active charcoal at a temperature in the range'of `100 to 300 F. After the butylenes and the propylene have reacted to form secondary butyl chloride and isopropyl chloride, respectively, the

unreacted hydrocarbons are removed from the'- chlorides by fractional distillation and recycled to the dehydrogenation step. The.4 chlorides are mixed with about 1.5 times their weight of a feed stock comprising chiey isopentane, and

the mixture is emulsified, by, vigorous. mechanical l stirring, with about three-fourths of its own volume of sulfuric acidhaving 102 percent HzSOi by weight. After about three hours at a temperature of about 68 FL, during which the hydrogen chloride regenerated is recycled to the step for making chlorides, the emulsion is allowed to settle into two layers. The lower or acid layer is removed, and the upper or hydrocarbon layer is washed with dilute alkali and then fractionally distilled. Of the hydrocarbons othetthan isopentane, about 98 per cent byweight boil between 85 and 410 F.; this fraction, which is completely parafnic, amounts to about .90 per cent by weight of the theoretical yield based on the formation of nonane.

l Example 1V A feed stock comprising chiefly propane is dehydrogenated with the aid of a dehydratedbauxite catalystat a pressure slightly above atmospheric, at a temperature within the range of about 1050 to 1300F., and'at a space velocity of about 1000 volumes of propane, cal 4lated to 32 F. and 1 atmosphere, per volumel f catalyst per hour. The resultant mixture is cooled to between about 100 and 195 F., mixed with an excess of anhydrous hydrogen chloride and subjected to the action of stannic chloride deposited on dehydrated bauxite. After the reaction forming isopropyl chloride is substantially complete, the reaction mixture is fractionally distilled into a light-gas fraction comprising chiey .hydrogen and methane, which is discarded; into a hydrogen chloride fraction, which is recycled to the step for the formation of isopropyl chloride; into a propane fraction, which is recycled to the dehydrogena ionstep; and into an isopropyl chloride filtion, which is mixed with about 1.8 times its wn Weight of a feed stock comprising chie/fly isopentane. The mixture comprising isopropyl chloride and isopentane is emulsiiied/with about three-fourths of its' own volume of sulfuric acid having a strength equivalent 102 per. cent HzSOr by weight. After being kept vigorously stirred for about four ho s at about 70 F., the emulsion is allowed to, ettle, and the lower or acid layer is removed. rThe upper or hydrocarbon layer is washed with dilute alkali and fractionally distilled. After removal of isopentane, the fraction boiling from 85 to 410 F. amounts to about 99 per cent by weight of the hydrocarbon product and to 78 per cent by weight of the theoretical yield based on the formation of octane.

" Example V There is mixed with astream of commercial propane, consisting of over 95 per cent propane, a stream of chloride, with a mole ratio of propane to chlorine of about 8 to 1. This mixture is rapidly heated to a temperature of about 630 F. and is maintained at that temperature fora time long enough for at least 90 per cent of theA chlorineto react.

of approximately equal parts of fresh and recy-l cled acid. The 4resultant liquid mixture, or

emulsion, is passed rapidly through an elongat ed tube oil of restricted cross-sectional area, which is immersed in -a liquid bath which takes up the heat of reaction and maintains the reaction temperature in the neighborhood oi' 75 F. The turbulence in the stream, as a result of the rapid flow through the tube coil, aids to maintain an intimate mixture -of the liquid reactants. After a reaction time of about 12 minutes the elliuent is passed to a separating system, wherein the hydrocarbon I,material vis separated from the sulfuric acid material and from hydrogen chloride. The free acid in the hydrocarbon material is neutralizedand removed by :an alkali wash,

Vand the stream is passed to a fractionating sys- Example VI Natural gas is cracked at low pressure to convert the paraiiins having two or more carbon atoms per molecule into oleiins, chiefly ethylene and propylene. Hydrogen chloride is admixed to the resultanteilluent from the cracking coil, and the mixture is passedat low pressure over zinc chloride. adsorbed on pumice at about 300 F., whereby alkyl chlorides, chiefly ethyl chloride and isopropyl chloride, are formed. The resulting mixtureis cooled, yand the alkyl chlorides are extracted by absorption in natural gasoline in a countercurrent absorption tower. The resultant mixture of natural gasoline and alkyl chlorides is subjected to the action of aluminum chloride under alkylation conditions, whereby alkylation of natural-gasoline constituents is effected with elision of hydrogen chloride. The gasoline recovered from the'reaction Vmixture, by fractional distillation and washing with dilute caustic, is much superior to the original natural gasoline by being less volatile and by having an increased antiknock rating.

In view of the many possible modifications of the process that will be obvious to those skilled in the art, the invention should not be limited unduly by the foregoing specificationl and examples, b'ut it should be understood to be extensive in scope and equivalents, within the scope of the appended claims.

I claim:

1. A process for the manufacture of motor-fuel hydrocarbons, which comprises c racking natural gas at low pressure to form olens, reacting the resultant olens with hydrogen chloride to form alkyl'chlorides, extracting the resultant alkyl chlorides by absorption with natural gasoline, subjecting the resultant mixture of natural gasoline and-alkyl chlorides to the action of aluminum chloride under alkylation conditions, whereby motor-fuel hydrocarbons are formed by alkylation of natural-gasoline constituents, and separating the resultant motor-fuel hydrocarbons.

2. A process for the production of branchedchain paraln hydrocarbons, which comprises converting an aliphatic hydrocarbon selected from the group consisting of oleiins and paraflins of low molecular weight into non-primary alkyl halides, passing a gaseous eilluent of said conversion comprising an alkyl halide so produced and unreacted hydrocarbons to an absorption zone, contacting said gaseous effluent in said absorption zone with a liquid paraiflnic hydrocarbon fraction boiling in the lower part of the motor fuel range and containing at least one branched-chain paraffin to separate alkyl halides so produced `boiling in the motor fuel range, which comprises passing a normally gaseous paraffin hydrocarbon to a dehydrogenating zone to form normally gaseous unsaturated hydrocarbons, passing ltheresultant unsaturated hydrocarbons without separation from accompanying saturated hydrocarbons to a reaction zone to convert said unsaturated hydrocarbons into alkyl halides, passing. the resultant mixture to a separating means to separate alkyl halides from accompanying hydrocarbons by absorption ofy said alkyl halides with a normally liquid saturated hydrocarbon fraction boiling in the lower part of the motor fuel range and higher than said accompanying hydrocarbons, subjecting the resultant mixture of normally liquid saturated hydrocarbons and alkyl halides to suitable alkylation conditions to form paraffin hydrocarbons inthe motor fuel range, and subsequently passing the alkylation efliuent to a separating means to remove a hydrocarbon fraction in the motor fuel range so produced.

4. A process for the manufacture ofvhydrocarbons boiling in the motor fuel range, which comprises dehydrogenating normally gaseous paraffin hydrocarbons to form normally gaseous unsaturated hydrocarbons, subjecting the resultant unsaturated hydrocarbons without separation from accompanying saturated hydrocarbons to reaction with ay hydrogen halide to form alkyl halides, separating resultant alkyl halides from accompanying hydrocarbons by absorption with a normally'liquid saturated hydrocarbon fraction boiling in the lower part of the motor fuel range, subjectingghe resultant mixture of said normally liquid saturated hydrocarbons and alkyl halides to the action of aluminum chloride under alkylation conditions to form hydrocarbons in the motor fuel range by alkylation of said normally liquid saturated hydrocarbons with said alkyl halides, and separating from the alkylation eiliuent a hydrocarbon fraction in the motor fuel range so produced.

5. A process for manufacturing hydrocarbons boiling in the motor fuel range from lower boiling hydrocarbons, which comprises dehydrogenating normally gaseous paraffin hydrocarbons having more than two carbon atoms per molecule to form gaseous olens, reacting substantially all the resultant olens with hydrogen chloride under conditions adapted to form alkyl chlorides therefrom, separating from the reaction products resultant alkyl chlorides by absorption with a normally liquid saturated hydrocarbon material of high isoparafn content and of relatively high volatility, separating also a fraction comprising essentially unreacted normally gaseous parafln hydrocarbons and returning at least a portion thereof to said dehydrogenation step, reacting a resultant mixture containing said saturated hydrocarbon material of relatively high volatility with said alkyl chlorides in the presence of sulfuric acid under conditions adapted to alkylate said saturated hydrocarbon material, separating fro-m the alkylation eiliuent hydrogen chloride as a light gaseous phase and returning at least a portion thereof for reaction with additional olefin and separating also a hydrocarbon material as a liquid phase and recovering therefrom normally liquid hydrocarbons of less volatility than the absorbent material and boiling in the motor fuel range.

6. A p rocess for the production of branchedchain saturated hydrocarbons, which comprise: converting a low-boiling aliphatic hydrocarbon to form an alkyl halide, passing a gaseous effluent of said conversion comprising an alkyl halide so `produced and unreacted hydrocarbons to an absorption zone, contacting said gaseous effluent in said absorption zone with a liquid saturated hydrocarbon fraction boiling in the lower part of the motor fuel range and comprising an alkylatable hydrocarbon to separate an alkyl halide so produced from said conversion effluent, passing a resulting rich absorption liquid from said absorption zone to an alkylation zone and therein subjecting said rich liquid to alkylation conditions to form a branched-chain saturated hydrocarbon of higher molecular weight by reactions involving said alkyl halide and said alkylatable hydrocarbon, and subsequently separating from an effluent of said alkylation zone a fraction'coo'rprising said branched-chain saturated hydrocarbon of higher molecular weight so produced.

7. The process of claim 6 in which said lowboiling aliphatic hydrocarbon converted to an alkyl halide is a normally gaseous paraflin, said alkylatable hydrocarbon is a low-boiling7 isoparafiin and a liquid acid alkylation catalyst is employed in said alkylation zone.

FREDERICK E. FREY. 

